Human history has shown that whenever power is concentrated in the hands of a few, or just one, corruption is bound to take place regardless of the belief system of the one in whose hand the power is concentrated. That's
why historically unions played a vital role as a check and balance on unfettered corporate power. Obviously unions have also struggled with the same fallen nature manifested as corruption that corporatists have.

Nowadays, unfortunately, unions do not primarily serve the needs of their workers but are more or less a funding stream and campaign platform for the Democrat Party. So while unions have a seat at the table, the workers
are worse off.